Method for the production of printed surfaces

ABSTRACT

A method for the production of printed surfaces which are fluorescent under ultraviolet (UV) light uses either a single color or four-color print process in which the base colors of yellow, blue and red and special color tones contain fluorescent pigments, which are not visible under normal light but visible under UV light, in a fixed ratio to the pigments which are colorfast under high intensity light. The method of this invention can be carried out easily to apply and the numerous printing steps previously required are avoided. One advantage is that pictures printed with fluorescent colors appear to give a complete three-dimensional effect at night under UV light with an authentic stepless color reproduction of all tones when daylight effect.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method for producing printed surfaces whichfluoresce under ultraviolet (UV) light.

2. Description of Related Art

It is known to use fluorescent dyestuffs in combination with normaldyestuffs for various effects.

Fluorescent dyestuffs are mixed with normal dyestuffs to make the colorbrighter in daylight. The dyestuffs which are non-visible or fluoresceunder ultraviolet light (UV light) are also particularly used in thetheatre for special effects, their dramatically fluorescent propertiesunder UV illumination being exploited.

It is known that for use in signs and in advertising, adhesive,fluorescent foils are cut into letters and/or figures, emblems, logosand the like, which for example are stuck to a window pane or to acorresponding pane or panel made of glass, Plexiglas or a similartranslucent material that forms a carrier for signs or advertising.

In order to impart the desired, glowing, neon-like effect to the sign oradvertisement, it must be illuminated by a so-called non-visible orblack light.

An adhesive, fluorescent foil with a translucent layer, which isimpermeable or substantially impermeable for UV radiation, is disclosedin PCT International Publication WO-A-93/01581.

A disadvantage in the use of such adhesive, fluorescent foils in theform of cut-to-size letters, figures, emblems, logos and the like, insigns or in advertising is that merely letter features, logos anduniform color areas can be highlighted, and photographic reproductionsand pictures in general cannot be depicted in color gradations andtransitions. Furthermore, it is disadvantageous that numerous foilcharacters or patterns must be fabricated and cut in complex individualsteps and the individual, monochrome foil patterns must be positionedand glued by hand within the scope of the actual formation of the signor advertising surface.

A method is known from U.S. Pat. No. 4,652,464, for printing art oradvertising graphics using visible and/or non-visible, fluorescentdyestuffs and non-fluorescent dyestuffs in multiple print series ofcolors, each print series being implemented with one predetermined printpattern. Art and advertising graphics are produced in the printingprocess with the property of depicting an object with a smoothtransition under distinctly different lighting conditions when theobject is observed under illuminations which vary between daylight orincandescent light up to UV light.

In this method visible and/or non-visible, fluorescent dyestuffs areused during the printing process, which are applied to previouslyselected areas of the picture in a predetermined pattern, in order toobtain the desired colors under normal light or daylight and in order toamalgamate these fluorescent dyestuffs with the non-fluorescentdyestuffs under UV light, so that the fluorescent dyestuffs are blendedor concealed under normal light.

The relative ratio and the colors and different color tones of thenon-fluorescent dyestuffs and of the visible and non-visible,fluorescent dyestuffs are selected in advance, in order to achieve agradual, fine transition on the picture when it is observed under lightconditions which alternate between daylight and UV light, or in order toblend or shade the effect, or in order to reduce the intensity of thefluorescent dyestuffs in specific areas so as to achieve a more naturaland gentler effect under UV light.

The disadvantage of the method according to U.S. Pat. No. 4,652,464 isthat the printing process must be modified in a complex manner in orderto include the application in addition of fluorescent dyestuffs. Also, aprinting process is required which is structured in many printing stepswith the application of a multiplicity of specific fluorescent dyestuffsand, furthermore, predetermined areas with gradations both of the normalcolors and also of the non-visible, fluorescent dyestuffs must beprinted, in order to examine the desired effect of not impairing thefluorescent dyestuffs, which are applied to the picture, by the normaldaylight dyestuff patterns.

A method for producing surfaces which are luminous at night is knownfrom German Patent Reference DE-A1-196 20 090, in which a wire printermethod with luminous colors red, green, blue is used so that the printedsurface is luminous at night. In a second print run with translucentcolors the motif depicted on the printed surface can also be madevisible in daytime. The second print run serves at the same time as UVand reaction protection of the luminous colors.

SUMMARY OF THE INVENTION

One object of this invention is to provide a method that avoids therequired multiplicity of printing steps and in particular the complexadjustment of the fluorescent colors in the printing process.

This object is achieved by features of this invention as described inthe claims and this specification.

Particular requirements or additional steps are no longer required.Non-visible, fluorescent dyestuffs were not used in the mentioned formin the four-color and multi-color printing method. The advantages ofthis invention reside particularly in the fact that, instead of amultiplicity of printing steps using non-visible, fluorescent printcolors and paints, the normal practice printing steps are implemented.In this connection, as also with four-color and multi-color printingwith the conventional primary colors, in the lithographic composition anauthentic pictorial reproduction is effected by targeted alteration ofthe color parameters of each individual print color and in the printingitself a fine adaptation of the perceived color is effected by analteration of the applied color quantity. This alteration method whichis known to any printer can immediately be implemented without specialtraining or other know-how in a non-problematic manner.

DESCRIPTION OF PREFERRED EMBODIMENTS

In one embodiment of this invention, added to the print colors and/orpaints are organic pigments in the range of 15% to 20%, fluorescentpigments in the range of 5% to 30% and optically active substances inthe range of 0% in one kilogram of color. With these measures, a veryweak luminosity of the colors is achieved.

With the measures set forth in claim 3, a weak luminosity of the colorscan be achieved, and with the measures set forth in claim 4, an averageluminosity of the colors can be achieved. With the measures set forth inclaim 5, a strong luminosity of the colors is achieved and finally avery strong luminosity of the colors is achieved with the measures ofclaim 6.

This invention also extends to a single color printing method. In thecase of print colors, it relates to highly colorfast print colors.Special color tones can likewise be taken into account.

By printing with fluorescent colors, the printed reproductioncorresponds to the model in its color-fastness and color gradation indaylight and appears as a completely normal poster or advertisingsurface, though with the effect that by using the fluorescent dyestuffseven in daylight greater luminosity of the colors is already expressed,so that the reproduction strikes the observer substantially sooner thana conventional four-color print poster.

As the most distinctive advantage, the picture which is printed withfluorescent colors, the advertising graphics, advertising surface or thelike, glows entirely of its own accord at night under UV light with anauthentic color reproduction in comparison with the daylight effect,comparable to the brilliance of a television picture, though even moreeffectively in all color gradations. Three-dimensional effects areproduced in the reproduction with the luminosity of a slide projectionand a deep three-dimensional effect is achieved, so that the observerpays particular, attention. Furthermore, the picture surface which isapplied to a dark background glows of its own accord at night under UVillumination, since the UV light source, contrary to white light, throwsno scattered light.

The printing process according to this invention comprises conventionalmethods and materials, this invention forming in particular thecombination of the function of the elements.

The ratio of a percentage mixture of fluorescent pigments andnon-fluorescent pigments varies on the one hand according to theindividual colors or color tones, the different print stocks and, on theother hand, according to the printing methods used, for example theoffset or the screen print method. The print colors can be described asfollows: contentional primary colors and special color tones incombination with organic pigments, fluorescent pigments, and opticallyactive substances, the mixture of organic pigments, fluorescent pigmentsand optically active substances being effected in different percentageratios according to the printing method, according to primary colors andspecial tones and according to print stocks.

A preferred standard value for the ratio is given according to oneembodiment of this invention in that the pigment addition to onekilogram of color in the case of organic pigments is in the range of0.5% to 5%, in the case of fluorescent pigments in the range of 15% to80% and in the case of optically active substances in the range of 0.5%to 1%.

This invention is described in greater detail by the following example.

Possibly, a photographically reproduced western city silhouette is to beprinted, with the back of a person being reproduced in the foreground.

This motif is produced in the four-color printing method by usingnon-visible, fluorescent print colors and paints, the color gradationbeing achieved, in the printing process step of the lithographiccomposition, as also in the case of the conventional four-color printingmethod, corresponding to the model by means of alteration of the colorparameters and a fine adaptation of the perceived color being effectedin the print itself by means of a corresponding increase or decrease ofthe color quantity applied in the printing. The adjustment occurs takinginto account the use of fluorescent dyestuffs, which do not correspondto the Euroscale norm, preferably by eye.

The advertising surfaces which fluoresce by means of the proposed methodcan be produced for any purpose, also therefore for packagings which areused with UV illumination in the gastronomic sphere.

What is claimed is:
 1. In a method for producing printed surfaces whichfluoresce under an ultraviolet illumination by using print colors and/orpaints with pigments which are non-visible in normal light and arevisible in an ultraviolet light, the improvement comprising: setting adefined ratio in a four-color printing method between one group offluorescent pigments of print colors yellow, blue (cyan) and red(magenta) and special color tones, and a second group of non-fluorescentpigments of the print colors.
 2. In the method according to claim 1,wherein to the print colors and/or paints organic pigments are added ina first range of 15% to 20%, fluorescent pigments are added in a secondrange of 5% to 30%, and optically active substances are added in a thirdrange of 0% in one kilogram of color.
 3. In the method according toclaim 1, wherein to the print colors, organic pigments are added in afirst range of 5% to 15%, fluorescent pigments are added in second rangeof 10% to 50%, and optically active substances are added in a thirdrange of 0.1% to 0.5% in one kilogram of color.
 4. In the methodaccording to claim 1, wherein to the print colors and/or paints organicpigments are added in a first range of 0.5% to 5%, fluorescent pigmentsare added in a second range of 15% to 80%, and optically activesubstances are added in a third range of 0.5% to 1% in one kilogram ofcolor.
 5. In the method according to claim 1, wherein to the printcolors and/or paints organic pigments are added in a first range of 0.5%to 3%, fluorescent pigments are added in a second range of 20% to 85%,and optically active substances are added in a third range of 1% to 2%in one kilogram of color.
 6. In the method according to claim 1, whereinto the print colors and/or paints organic pigments are added in a firstrange of 0.5% to 1%, fluorescent pigments are added in a second range of2% to 90%, and optically active substances are added in a third range of2% to 5% in one kilogram of color.